Hydrodynamic and Suspended-Solids Concentration
Measurements in Suisun Bay, California, 1995
By Jay I. Cuetara, Jon R. Burau,
and David H. Schoellhamer
U.S. GEOLOGICAL SURVEY
Water Resources Investigation Report 01-4086
Sacramento, California 2001
Main Text of report (1.8 MB PDF)
Appendix_A-G (2.5 MB PDF)
Appendix_H-N (1.2 MB PDF)
Appendix_O-V (1.9 MB PDF)
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ABSTRACT
Sea level, current velocity, water temperature, salinity (computed from conductivity and temperature), and suspended-solids data collected in
Suisun Bay, California, from May 30, 1995, through October 27, 1995, by the U.S. Geological Survey are documented in this report. Data were
collected concurrently at 21 sites. Various parameters were measured at each site. Velocity-profile data were collected at 6 sites, single-point
velocity measurements were made at 9 sites, salinity data were collected at 20 sites, and suspended-solids concentrations were measured at 10
sites. Sea-level and velocity data are presented in three forms; harmonic analysis results; time-series plots (sea level, current speed, and
current direction versus time); and time-series plots of low-pass-filtered time series. Temperature, salinity, and suspended-solids data are
presented as plots of raw and low-pass-filtered time series.
The velocity and salinity data presented in this report document a period when the residual current patterns and salt field were transitioning
from a freshwater-inflow-dominated condition towards a quasi steady-state summer condition when density-driven circulation and tidal
nonlinearities became relatively more important as long-term transport mechanisms. Sacramento-San Joaquin River Delta outflow was high prior to
and during this study, so the tidally averaged salinities were abnormally low for this time of year. For example, the tidally averaged salinities
varied from 0-12 at Martinez, the western border of Suisun Bay, to a maximum of 2 at Mallard Island, the eastern border of Suisun Bay.
Even though salinities increased overall in Suisun Bay during the study period, the near-bed residual currents primarily were directed seaward.
Therefore, salinity intrusion through Suisun Bay towards the Delta primarily was accomplished in the absence of the tidally averaged, two-layer
flow known as gravitational circulation where, by definition, the net currents are landward at the bed. The Folsom Dam spillway gate failure on
July 17, 1995, was analyzed to determine the effect on the hydrodynamics of Suisun Bay. The peak flow of the American River reached roughly 1,000
cubic meters per second as a result of the failure, which is relatively small. This was roughly 15 percent of the approximate 7,000 cubic meters
per second tidal flows that occur daily in Suisun Bay and was likely attenuated greatly. Based on analysis of tidally averaged near-bed salinity
and depth-averaged currents after the failure, the effect was essentially nonexistent and is indistinguishable from the natural variability.
CONTENTS
Abstract
Introduction
Purpose and Scope
Study Area
Geographic Setting
Tides
Currents
Hydrologic Conditions
Meteorological Conditions
Sediment
Acknowledgments
Findings
Tidal Timescale Variability
Currents
Salinity
Residual Timescale Variability
Currents
Salinity
Affect of Folsom Dam Spillway Gate Failure on Suisun Bay Hydrodynamics
Sediment Transport
Summary
References Cited
Appendix A: Data Reduction Details and Data Presentation
Data Reduction Details
Acoustic Doppler Current Profiler Data
Sea-Level Data
Salinity Data
Conductivity-Temperature Sensors
Conductivity-Temperature-Depth-Optical Backscatterance Sensors
Salinity Computation
Suspended-Solids Concentration Computation
File Formats
Time-Series File Format
Acoustic Doppler Current Profiler File Format
Data Presentation
Plotting of Oceanographic Data
Low-Pass Filter
Harmonic Analysis
Appendix B--Station BEN
Appendix C--Station BULLS
Appendix D--Station CARQ
Appendix E--Station MET
Appendix F--Station CUT
Appendix G--Station GARN
Appendix H--Station GARNW
Appendix I--Station GC
Appendix J--Station GDOL
Appendix K--Station GS
Appendix L--Station HC
Appendix M--Station HDOL
Appendix N--Station HS
Appendix O--Station MAL
Appendix P--Station MART
Appendix Q--Station MID
Appendix R--Station MOTH
Appendix S--Station RYER
Appendix T--Station RYERE
Appendix U--Station SPOON
Appendix V--Station WICK
Water Resources of California